For traditional phone systems, people give out their phone number to anyone they wish to communicate with them at a later date, even if they only wish to communicate with the other person in a limited fashion or for a limited time (personal date, temporary business relationship, internet friends, etc). If a person wishes to avoid further communications from a particular person, the person can use a call blocking service to block calls but only if the other person's telephone number(s) are known. Alternatively, the person can cancel the current phone number and obtain a new number that is then provided to everyone who the people desires to receive calls from.